The purpose of this study is to analyze the reasons for the decline in fertility in postwar Japan. The empirical evidence gathered through questionnaires administered in six prefectures in Japan, along with macro-economic data and demographic data published by various branches of the Japanese government, will be analyzed with the aid of economic and demographic theories. The objective of this study is to seek interrelationships between fertility measured in various ways and selected economic and social variables in post-1945 Japan.